Liver parasites and body condition in relation to environmental contaminants in caribou (rangifer tarandus) from labrador, Canada.(ARCTIC)(Report)

ABSTRACT. Over the last several decades, elders and hunters of the Innu Nation in Labrador, Canada, have expressed concerns over perceived declines in environmental health and the integrity of country food, including caribou. The primary objective of this study was to determine links between specific health parameters and contaminants found in caribou from the George River herd. Twenty-seven caribou killed by local Innu hunters between February and December 2001 were evaluated for gross and microscopic pathology, body condition, liver parasitology, and contaminant levels in kidney and fat. Overall, the sampled caribou appeared to be in adequate body condition for the time of year, and no clinically significant lesions were found. Concentrations of selenium, metals (Hg, Cd, and Pb), 20 organochlorine pesticides (HCB, [alpha]-HCH, [gamma]-HCH, aldrin, dieldrin, methoxychlor, mirex, [alpha]- and [beta]-endosulfan, heptachlor, heptachlor epoxide, [gamma]-CHL, cis-CHL, trans-nonachlor, and o,p'- and p,p'-DDD, DDE, DDT), and 24 PCB congeners were within the ranges reported for caribou in Canada. In general, contaminant levels were relatively low, with the exception of cadmium in kidneys (geometric mean: 6.5 [micro]g/g wet weight; range: 1.5-44.0 [micro]]g/g). Two types of liver parasites were found: the liver fluke Fascioloides magna (prevalence: 78%; geometric mean abundance: 4.2 flukes/caribou) and a tapeworm larva consistent with Taenia hydatigena (prevalence: 50%; geometric mean abundance: 0.6 larvae/caribou). Using multiple variable regression analysis, we found renal concentrations of cadmium to be positively associated, and selenium to be negatively associated, with F. magna abundance.

Key words: body condition, environmental contaminants, liver fluke, Fascioloides magna, parasites, Rangifer tarandus, cadmium, Innu people, Labrador, George River caribou herd

RESUME. Ces dernieres decennies, les aines et les chasseurs de la nation montagnaise du Labrador, au Canada, ont exprime des inquietudes au sujet du declin de la sante de l'environnement et de l'integrite de la nourriture provenant de la campagne, telle que le caribou. L'objectif principal de cette etude consistait a determiner les liens qui existent entre certains parametres de sante precis et les contaminants se trouvant dans le caribou du troupeau de la riviere George. Vingt-sept caribous ayant ete tues par les chasseurs montagnais de la region entre les mois de fevrier et de decembre 2001 ont subi des examens pathologiques macroscopiques et microscopiques, en plus d'avoir ete evalues pour en determiner l'etat du corps, la parasitologie du foie et les taux de contaminants dans le foie et le gras. Dans l'ensemble, l'etat des corps de caribous echantillonnes semblait adequat pour cette periode de l'annee et aucune lesion clinique importante n'a ete signalee. Les concentrations de selenium, de metaux (Hg, Cd et Pb), de 20 pesticides organochlores (HCB, [alpha]-HCH, [gamma]-HCH, aldrine, dieldrine, methoxychlore, mirex, [alpha]- et [beta]-endosulfane, heptachlore, heptachlorepoxyde, [gamma]-CHL, cis-CHL, trans-nonachlore ainsi que o,p'- et p,p'-DDD, DDE, DDT) et de 24 congeneres de PCB s'etablissaient dans les etendues signalees pour le caribou au Canada. En general, les niveaux de contaminants etaient relativement faibles, a l'exception du cadmium se trouvant dans les reins (moyenne geometrique: 6.5 [micro]g/g poids humide; etendue: 1,5-44,0 [mu]g/g). Deux types de parasites du foie ont ete trouves: la douve Fascioloides magna (prevalence: 78 %; abondance moyenne geometrique: 4,2 douves/caribou) et un cestode du genre Taenia hydatigena (prevalence: 50 %; abondance moyenne geometrique: 0,6 larves/caribou). Nous avons egalement realise une analyse de

INTRODUCTION

Caribou (Rangifer tarandus) is the dominant large terrestrial herbivore in many northern ecosystems. The George River herd (GRH) is the largest caribou population in eastern Canada. The range of the GRH includes much of Labrador and extends across the Ungava Peninsula well into the province of Quebec (Fig. 1). The GRH population underwent rapid growth up to the mid-1990s, when it was estimated at approximately 700000 animals, and has recently declined to approximately 400000 animals (R. Otto, pers. comm. 2007).

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Members of the Innu Nation in Labrador hunt caribou from the GRH on a seasonal basis. Caribou have important nutritional, cultural, and spiritual significance for the Innu people (Armitage, 1990; Loring, 1997), who are concerned for the health of Labrador caribou populations because of industrial development and other potential impacts on the ecosystem, such as environmental contaminants (Innes, 1998).